It is known that Coriolis-type mass flow meters can be used to measure the mass flow and/or the density of a fluid which is flowing in a pipeline into which the Coriolis-type mass flow sensor is inserted.
A special kind of such mass flow sensors wich the invention refers to has a single straight measuring tube. For reaching a sufficient operating temperature range of the mass flow sensor, the measuring tube consists of titanium or zirconium but not of stainless steel.
The measuring tube is set vibrating by the abovementioned exciter arrangement. When the Coriolis-type mass flow sensor is flowed through by a fluid, Coriolis forces act on the measuring tube. As a result, the part of the measuring tube on the fluid inlet side vibrates wich a phase shift with respect to its part on the fluid outlet side. This phase shift is a measure of the instantaneous mass flow rate. As it is known, the instantaneous density of the fluid is proportional to the instantaneous vibration frequency of the measuring tube and, therefore, can be measured, too.
The phase shift is tapped by means of, for example, two sensor arrangements, of which one is arranged on the side of the part of the measuring tube on the fluid inlet side and one is arranged on the side of the part of the measuring tube on the fluid outlet side.